(CNSNews.com) - On the day after a jury found George Zimmerman not guilty of murdering Trayvon Martin, President Obama on Sunday called Martin's death a "tragedy" for America.

The United States, the president said, is a "nation of laws, and a jury has spoken." Obama also worked a gun gun control message into his eleven-sentence statement, saying Americans should ask themselves "if we're doing all we can to stem the tide of gun violence that claims too many lives across this country on a daily basis." (See Obama's full statement below.)

The Justice Department, which is being petitioned to bring civil rights charges against Zimmerman, also issued a statement on Sunday, saying it has "an open investigation into the death of Trayvon Martin."

"The Department of Justice’s Criminal Section of the Civil Rights Division, the United States Attorney’s Office for the Middle District of Florida, and the Federal Bureau of Investigation continue to evaluate the evidence generated during the federal investigation, as well as the evidence and testimony from the state trial.

"Experienced federal prosecutors will determine whether the evidence reveals a prosecutable violation of any of the limited federal criminal civil rights statutes within our jurisdiction, and whether federal prosecution is appropriate in accordance with the Department’s policy governing successive federal prosecution following a state trial," the brief statement concluded.

Harvard Law Professor and famed defense attorney Alan Dershowitz told Fox News's Mike Huckabee on Sunday that the Justice Department generally doesn't investigate civil rights violations committed by one individual against another unless that individual works for the state or the federal government.

"The violation of civil rights usually involves the state -- the government -- violating civil rights. George Zimmerman can't really alone violate the civil rights of an individual, even if he were to be guilty of the crime," Dershowitz said.

Nevertheless, Benjamin Todd Jealous, the head of the NAACP, is pressing the Justice Department to file a civil rights case against George Zimmerman.

In a message circulated by the liberal activist group MoveOn.org, Jealous noted that although a jury has acquitted Zimmerman, "we are not done demanding justice for Trayvon Martin.

"We're calling on the U.S. Justice Department to open a civil rights case against George Zimmerman and have launched a petition to Attorney General Eric Holder."

The Department of Justice has closely monitored the State of Florida's prosecution of the case against George Zimmerman in the Trayvon Martin murder since it began. Today, with the acquittal of George Zimmerman, it is time for the Department of Justice to act.

The most fundamental of civil rights—the right to life—was violated the night George Zimmerman stalked and then took the life of Trayvon Martin. We ask that the Department of Justice file civil rights charges against Mr. Zimmerman for this egregious violation.

President Obama, in his statement, noted that the Zimmerman case had stoked strong passions, but he called for "calm reflection."

Here is Obama's statement, in its entirety:

The death of Trayvon Martin was a tragedy. Not just for his family, or for any one community, but for America. I know this case has elicited strong passions. And in the wake of the verdict, I know those passions may be running even higher. But we are a nation of laws, and a jury has spoken. I now ask every American to respect the call for calm reflection from two parents who lost their young son. And as we do, we should ask ourselves if we’re doing all we can to widen the circle of compassion and understanding in our own communities. We should ask ourselves if we’re doing all we can to stem the tide of gun violence that claims too many lives across this country on a daily basis. We should ask ourselves, as individuals and as a society, how we can prevent future tragedies like this. As citizens, that’s a job for all of us. That’s the way to honor Trayvon Martin.

President Obama, commenting on the killing of Trayvon Martin back on March 22, called the case a tragedy but said he had to be "careful about my statements to make sure we're not impairing any investigation that's taking place."

But the president did say at the time, "If I had a son, he'd look like Trayvon."